Light-sensitive diazo compounds and light-sensitive material containing them

ABSTRACT

Light-sensitive diazo compounds of a new class are prepared by diazotizing aromatic amines of the formula IN WHICH R1 is an alkyl, aralkyl or aryl group, Y is a fluorine, chlorine or bromine atom, and IS A TERTIARY AMINO GROUP THAT MAY BE A SATURATED HETEROCYLIC RING. Light-sensitive material (papers, planographic printing plates, etc.) sensitized with salts of these compounds, e.g., with a 4-dialkylamino-3-halo-2-alkylthiobenzene diazonium salt or a 4-dialkylamino-3-halo-2-(4&#39;&#39;-methylphenylthio)-benzene diazonium salt, are developable by reaction with aromatic polyvalent phenols to form dark-colored azo dyestuff images having improved water-fastness and background contrast.

United States Patent [72] Inventors Adrianus Marie Petrus Hectors;

Hubertus Johannes Wilhelmus Pecasse, 9 both of Venlo, Netherlands [21]Appl. No. 736,576 [22] Filed June 13, 1968 [45] Patented Oct. 26, 1971[73] Assignee Van Der Grinten N.V.

Venlo, Netherlands [32] Priority June 19, 1967 [33] Netherlands [31]6708503 [54] LIGHT-SENSITIVE DIAZO COMPOUNDS AND LIGHT-SENSITIVEMATERIAL CONTAINING THEM 16 Claims, No Drawings [52] US. Cl 96/91,96/33, 96/49, 260/141 [51] Int. Cl G03c1/52, C07c 113/04, C07c 113/00[50] Field of Search 96/49, 75, 91; 260/141, 142

[56] References Cited UNITED STATES PATENTS 3,169,869 2/ 1965 Hendrickxet a1. 96/91 3,261,684 7/1966 Wilders et al 96/49 3,407,066 10/ 1968Mustacchi et a1.. 96/91 3,416,925 12/1968 Sus et a1 96/91 3,442,6505/1969 Hendrickx et a]. 96/91 3,442,651 5/1969 Hendrickx et a1. 96/913,442,652 5/1969 Hectors et a1 96/49 X OTHER REFERENCES Landau, R.,Fascicules 1 a 8," 1960, p. 51, 94 and 95. Kosar, J Light-SensitiveSystems, 1965, p. 203.

Primary Examiner-Ronald H. Smith Assistant Examiner-Charles L. Bowers,.Ir. Attorneys-Albert C. Johnston, Robert E. lsner, Lewis H.

Eslinger and Alvin Sinderbrand ABSTRACT: Light-sensitive diazo compoundsof a new class are prepared by diazotizing aromatic amines of theformula SR1 Y R;

in which R is an alkyl, aralkyl or aryl group, Y is a fluorine, chlorineor bromine atom, and

is a tertiary amino group that may be a saturated heterocylic ring.Light-sensitive material (papers, planographic printing plates, etc.)sensitized with salts of these compounds, e.g., with a4-dialkylamino-3-halo-2-alkylthiobenzene diazonium salt or a4-dia1kylamino-3-halo-2-(4'-methylphenylthio)- benzene diazonium salt,are developable by reaction with aromatic polyvalent phenols to formdark-colored azo dyestuff images having improved water-fastness andbackground contrast.

LIGHT-SENSITIVE DIAZO COMPOUNDS AND LIGHT- SENSITIVE MATERIAL CONTAININGTHEM This invention relates to a new process for the production oflight-sensitive diazo compounds and to new and improved diazo-typematerials containing the compounds.

Diazo compounds occupy an important place in applied chemistry. They areused, for instance as light-sensitive substances in the reproductionarts or as intermediates in many chemical syntheses.

The process according to the invention gives a new class of chemicalcompounds having valuable properties.

The most closely related known compounds are the 4-tert.amino-3-halobenzene diazo compounds, which are used in thediazo-type process for the sensitization of transparent and opaquesupports. Examples of such compounds are 4-diazo-2-chloro-N,N-diethylaniline (British Pat. No. 726,755),4-diazo-2-chloro-N-methyl-N-cyclohexylaniline British Pat. No.957,838),N-(4-diazo-2-chlorophenyl) morpholine (U.S. Pat. No. 2,541,488),4-diazo-2-fluoro-N,N-diethylaniline (French Pat. No. 1,398,576).Furthermore in the literature (Fiat Final Report 813, p. 352)4-diazo-3-ethylthio-N,N- diethylaniline has been mentioned for thesensitization of diazo-type material. This compound is qualified asunfit for use on account of its stained photodecomposition product.

According to the present invention, light-sensitive diazo compoundshaving new and improved properties and advantageous especially for theproduction of improved diazotype materials are prepared by diazotizingaromatic amines of the formula in which R, is an alkyl group, which maybe substituted or nonsubstituted or branched or nonbranched, or anaralkyl or aryl group, Y is a fluorine, chlorine or bromine atom, and

is a tertiary amino group that may be a saturated heterocylic ringlinked to the benzene nucleus via a nitrogen atom belonging to the ring.For the sake of brevity, the substituent Y is sometimes referred tohereinafter as a haloor halogen substituent.

The diazo compounds obtained according to the invention are in manyrespects quite comparable with the known 4- tert.amino-3-halobenzenediazo compounds. The invention, however, makes it possible to overcomethe disadvantages of this known and frequently used group of diazocompounds, to wit, the formation of light-colored and relatively poorlywater fast azo dyestuffs upon reaction with aromatic polyvalent phenols.The new diazo compounds in which R, is an alkyl group having no morethan five carbon atoms are, moreover, more light-sensitive, while thosein which R, is an aryl group show greater coupling activity than theknown compounds.

The diazo compounds according to the invention can be produced bydiazotizing amines of the formula by any of various known diazotizingmethods. Such methods have been described, inter alia, in Ullmann'sEncyklopadie der technischen Chemie 3 Aufl., 5. Band, pp. 791-794(1954).

The amino compounds of the formula (1) can be produced from a2,3,4-trihalonitrobenzene satisfying the formula in which each of Y,, Y,and Y ;is a halogen atom, The 2,3,4- trihalo-l-nitrobenzene is reactedwith ammonia, whereby the halogen atom is ortho-position relative to thenitro group is replaced by a primary amino-group. The product thusformed is converted with a tertiary amine 4-ter.amino-3-halo-2-amino-L-nitrobenzene. Then the primary amino-group of this compound isdiazotized and the diazo group replaced by a halogen atom, according toSandmeyer. This halogen in turn is replaced by an alkylthio,aralkylthio, or arylthio group. The nitro group of the4-tert.amino-3-halo-2-(alkyl, branched alkyl, arakyl, or aryl)thio-l-nitrobenzene thus produced is reduced, and the amino group thusformed is diazotized.

The 2,3,4-trihalonitrobenzene to be converted into the compounds of theformula (1) in the above way may be, respectively,2,3,4-trichloro-l-nitrobenzene [prepared according to Rec. trav. chim.40, 67-69 (1921], 2,3,4-tribromonitrobenzene [prepared according to AttiAccad. Naz. Lincei, Rend. [5/15, 11, 583], or2,3,4-trifluor0-l-nitrobenzene [prepared according to J. Am. Chem. Soc.8194-99 1959)].

The compounds of the formula (2) can, if desired, be obtained bystarting with 2,3-difluro-l-nitrobenzene [prepared according to J. Am.Chem. Soc. 81 94-99 (l959)]2,3- dichloro-l-nitrobenzene [preparedaccording to Rec. Trav. Chim. 39, 446-447 (1920)], or2,3-dibromo-l-nitrobenzene [to be prepared according to Rec. Trav. Chim.25, 202 (1906), respectively, in the following way: The nitro group ofthe 2,3-dihalo-l-nitrobenzene is reduced and the amino group thus formedis tosylated; the compound thus obtained is nitrated, the tosylaminogroup sapgnified, and the amino group diazotized; and then the diazogroup is replaced by a halogen atom according to Sandmeyer. In this waya 4-halo- 2,3-di(fluoro, chloro, or bromo)-1-nitrobenzene is obtained.In an analogous way it is possible to produce a trihalogen compound thatis suitable as starting material, from a 2,3-dihaloaniline ornitrobenzene in which the halogen atom desired as substituent Y ispresent in ortho-position relative to the amino group or the nitro groupof the formula (1) and another halogen atom is present in meta position.

The compounds'of the formula (1) in which the tertiary amino group is adimethylamino-group can advantageously be produced by a general methodother than the one mentioned above. A 2,3-dihaloaniline in which thehalogen atom desired as substituent Y is present at least in orthoposition relative to the amino-group of formula (1) is tosylated,nitrated, nethylated, and then saponified to4-methylamino-3-(fluoro,chloro, or bromo)-2-halo-1-nitroben2ene. Thisproduct is methylated and reacted with a mercaptan. The resulting nitrocompound is reduced and the amino compound is finally diazotizcd.

The chemical reactions to be applied in the production of the aminocompounds of the formula (1), as well as the conditions under whichthose reactions proceed satisfactorily, are know per se. The mercaptanwith which the thio-substituent in ortho position is introduced may bealiphatic, arylaliphatic, or aromatic. Many such mercaptans are known.Their alkyl radical is either straight or branched, and may or may notbe substituted; the aryl radical is preferably a phenyl or napththylradical, which may be further substituted. Examples of suitablemercaptans are methyl, ethyl, propyl, n-butyl, isobutyl, pentyl, andhexylmercaptan, hydroxyethylmercaptan, 2,3- dihydroxypropylmercaptan,2-(methylamino)ethylmercaptan, 2-carboxymethylmercaptan,phenethylmercaptan, phenyl, otolyl, m-tolyl, p-tolyl, p-anisyl,p-hyroxy-phenyl, pchlorophenyl, p-bromophenyl, p-(Z-hydroxyethyl phenyl,ptertiarybutylphenyl, and Z-carboxyphenylmercaptan. The tertiaryamino-group may be cyclic or open chain.

The tertiary amino groups of the compounds of formula( 1) may correspondto those of para-tertiary amino diazo compounds known in the literature.The hydrocarbon linked to the tertiary nitrogen atom may carry furthersubstituents. Suitable tertiary amino groups are, for instance,dimethylaminodiethylamino, di-n-propylamino, di-n-butylamino,di-isobutylamino, di-n-hexylamino, N-methyl-N-benzylamino, N-ethyl-N-benzylamino, N-n-propyl-N-benzyl-amino, N-methyl-N-3,4-dichlorobenzylamino, N-methyl-N-cyclohexyl-amino,N-ethyl3N-cyclohexylamino, N-methyl-N-4'-methylcyclohexylamino,N-rnethyl-N-phenethylamino, N-butyl-N-benzylamino-N-ethyl-N-2-hydroxy-ethylamino, N-propyl-N-2-ethoxyethylamino, N-propyl-N-2-phenoxy-ethylamino, morpholino,piperidino, piperazino, N-acetylpiperazino, N- benzoylpiperazino,N-methylpiperazino, N-2-hydroxyethylpiperazino, pyrrolidino, and2,6'-dimethylmorpholino.

The diazo compounds according to the invention can be used while stillpresent in the liquid in which they have been produced. They arepreferably obtained in a known way from this liquid in the form of a drygranular powder. They may be present in the powder as a diazonium saltor in some other form, e.g., as a diazosulphonate, a diazoamine, or adiazosulphone, alone or mixed with other substances, such as acids orsalts.

According to the process of the invention the following diazo compoundsmay, for instance, be obtained:4-diazo-3-methylthio-2-chloro-N,N-dimethylaniline4-diazo-3-ethylthio-2-fluoro-N,N-dimethylaniline4-diazo-3-carboxymethylthio-Z-chloro-N,N-dimethylaniline4-diazo-3-ethylthio-2-bromo-N,N-dimethylaniline4-diazo-3-ethylthio-Z-chIoro-N,N-dimethylaniline4-diazo-3-ethylthio-Z-chloro-N,N-dibutylaniline4-diazo-3-n-propylthio-2-chloro-N,N-dimethylaniline4-diazo-3-isobutylthio-2-chloro-N,N-dimethylaniline4-diazo-3(2-hydroxyethylthio)-2-chloro-N,N-dimethylaniline 4-diazo-3-( 2'-ethoxyethylthio )-2-chloro-N,N-dimethylaniline4-diazo-3-ethlthio-2-chloro-N-methyl-N-cyclohexylaniline4-diazo-3-ethylthio-2-chloro-N,N-diethylaniline4-diazo-3-phenethylthio-2-chloro-N ,N-dimethylaniline4-diazo-3-phenylthio-2-chloro-N,N-dim ethylaniline 4-diazo-3-(4'-methylphenylthio )-2-fluoro-N,N- dimethylaniline 4-diazo-3 -(4'-methylpheny1thio)-2-chloro-N ,N- dimethylaniline 4-diazo-3-(4'-methylphenylthio )-2-bromo-N ,N- dimethylaniline 4-diazo-3-( 3-methylphenylthio)-2-chloro-N ,N- dimethylaniline 4-diazo-3-(4'-chlorophenylthio)-2-chloro-N,N- dimethylaniline 4-diazo-3-( 4-tert.butylphenylthio)-2-chloro-N,N- dimethylaniline 4-diazo-3-( 3 -methylphenylthio-2-chloro-N-methyl-N- benzylaniline 4-diazo-3-( 3'-methylphenylthio)-2-chloro-N-methyl-N- cyclohexylaniline 4-diazo-3-( 2'-methylphenylthio )-2-chloro-N,N- dimethylaniline 4 -diazo-3-( 4'-hydroxyphenylthio)-2-chloro-N ,N- dimethylaniline 4-diazo-3-( 4'-methoxyphenylthio )-2-chloro-N,N- dirnethylaniline 4-diazo-3-N-/B-naphthylthio-Z-chloro-N ,N-dimethylaniline 4-diazo-3-( 4'-methylphenylthio)-2-chloro-N,N-di-n-pentylaniline 4-diazo-3-(4'-methylphenylthio )-2-chloro-N ,N-di-n-hexylaniline4-diaz0-3-(4'-rnethylphenylthio )-2-chloro-N-methyl-N-isobutyl-aniline4-diazo-3-( 4 -methylphenylthio )-2-chloro-N-n-propyl-N-2ethoxy-ethylaniline 4-diazo-3-( 4 '-methylphenylthio)-2-chloro-N-n-propyl-N-2 phenoxy-ethylaniline 4diazo-3-( 4'-methylphenylthio )-2-chloro-N-ethyl-N-2 hydmxy-ethylaniline4-diazo-3-(4 '-methylphenylthio)-2-chloro-N-ethyl-N-2chloro-ethylaniline 4-diazo-3-(4 -rnethylphenylthio)-2-chloro-N-n-propyl-N- benzylaniline 4-diazo-3-( 4 -methylphenylthio)-2-chloro-N-n-butyl-N- benzylaniline3-(4'-methylphenylthio)-2-chlorophenis a saturated heterocyclicring. Themost accessible compounds are those in which is a dialkylamino, aN-alkyl-N-benzylamino, or a N-alkyl-N- cyclo-hexylamino group, with thealkyl groups having at most four carbon atoms; the benzyl or cyclohexylgroup may be nonsubstituted or substituted.

The diazo compounds according to the invention may be used, forinstance, as intermediates in chemical syntheses and as light-sensitivesubstances for the sensitization of supports, such as paper, metal,film, printing plates, etc.

Because the diazo compounds according to the invention have goodlight-sensitivity, bleach out clearly, and have a suitable couplingactivity they are eminently suited in the form of the diazonium salt forthe sensitization of diazo-type material.

For the sensitization of two-component diazo-type material4-diazo-N,N-dialkylanilines have long been used and are still being usedon a fairly large scale. Examples of such diazo compounds are4-diazo-N,N-dimethylaniline, 4-diazo-N,N- diethylaniline, and4-diazo-N-ethyl-N-2'-hydroxyethylaniline. Material sensitized with thesediazo compounds may have a transparent as well as an opaque support. ithas good keeping qualities, but its light-sensitivity, as measured bypresent-day standards, is rather low.

Of recent years highly light-sensitive diazo compounds have come intouse for the sensitization of diazo-type materials. These are mainlybenzene diazo compounds containing a tert. amino group in p-position andan etherified hydroxyl group in m-position relative to the diazo group,and having, if desired, a substituent such as alkoxy, alkyl, or halogenin para position relative to the etherified hydroxyl group. Among thesediazo compounds particularly those in which alkoxy groups are present inpositions 2 and 5 have good thermo-stability, in consequence of whichdiazo-type material sensitized therewith has reasonable resistance topresence in warm surroundings. It is known that heat has an acceleratingeffect on the decomposition of diazo compounds and that in practice, forinstance during transport in summer or storage in the tropics,diazo-type materials are often exposed to temperatures which areconsiderably higher than room temperature, sometimes even totemperatures of 40 to 50 C.

ln two-component diazo-type material, N-(4-diazo-2, 5-diethoxyphenyl)morpholine, inter alia, is used on a very large scale. Itis a disadvantage of this compound that its photodecomposition productis toned, so that the whiteness or the transparence of the backgroundareas of copies which have been made from diazo-type paper sensitizedwith this compound leaves much to be desired.

For the sensitization of diazo-type materials which have to yield copieswith a yellow or brown image, 4-diazo-2-chloro- N,N-diethylaniline isfrequently used in the one-component diazo-type process. This diazocompound is reasonably lightsensitive, and material sensitized therewithgives with buffered weakly alkaline phloroglucinol developers copieshaving yellow to pale brown azo dyestuff images, which have highabsorption for the ultraviolet copying light commonly used in thediazo-type process. Another compound sometimes used for thesensitization of transparent one-component diazo-type materials is4-diazo-2-chloro-N-methyl-N-cyclohexylaniline. Material sensitized withthis compound, when developed with weakly alkaline phloroglucinoldevelopers, also yields copies having brown azo dyestuff images.

- For the sensitization of transparent two-component diazotypematerials, compounds like 4-diazo-2-chloro-N,N-diethylaniline and4-diazo-2-chloro-N-methyl-N-cyclohexylaniline are not very suitable.Although these compounds bleach out clearly and their light-sensitivityis considerably higher than that of the 4-diazo-N,N-dialkylanilines, thematerials obtained therewith yield copies having azo dyestuff imageswhich are lighter and thus visually less contrasting then correspondingtwo-component diazo-type materials which have been sensitized with themore commonly used compounds, such as 4- diazo-N,N-dimethylaniline orN-(4-diazo-2,5-diethoxyphenyl)morpholine.

One-component diazo-type material which has been sensitized with a diazocompound according to the invention can be developed with the knownphloroglucinol-containing liquids to yield copies having azo dyestuffimages which are darker and more waterfast than the azo dyestuff imagesof copies on diazo-type material which has been sensitized with acorresponding compound lacking the thio-substituent.

For use in two-component diazo-type material, the diazo compoundsaccording to the invention provided with the lightest substituents areespecially suitable. They are particularly attractive for use intransparent two-component diazotype materials destined for makingintermediate copies for further reproduction on diazo-type material.

For the sensitization of printing plates, too, diazo compounds are oftenused. For this use mainly three categories are to be distinguished, towit: the oleophilic esters and amides of aromatic ortho-quinonediazides; the tanning diazo compounds, specifically condensationproducts of benzene diazo compounds with aldehydes, and the diazoniumsalts, which in combination with suitable azo-components (such asphloroglucinol) form oleophilic azo dyestuffs and also have ahydrophilic photodecomposition product.

The last-mentioned category of diazo compounds is also suitable for thesensitization of conventional diazo-type material. Thus from the DutchPat. applications Nos. 64.11713, 64.06149, and 295,561 diazo compoundsare known which are eminently suited for the sensitization of diazo-typematerial as well as for the sensitization of hydrophilic planographicsurfaces which are converted into a printing form by imagewise exposureand development with a liquid containing an azo-component. Theplanographic plates sensitized with diazo compounds, in which theformation of the image is effected by means of a diazo-type process, arereferred to below as diazo-type planographic plates.

The diazo-type planographic plates are obtained by sensitizing asupport, such as paper, aluminum or plastic foil, which has a so-calledplanographic surface, with a solution of a diazo compound. By aplanographic surface is to be understood a hydrophilic surface havingonly small water-absorption. Supports with a planographic surface arecommonly known and regularly used in the planographic and offsettechniques. The

paper supports consist of wet-strength paper (if desired, also providedwith one or more water-resistant layers) and a planographic layer inwhich a hydrophilic filler (such as silica, titanium dioxide, or bariumsulphate) and a hydrophilic organic binder that is insoluble or has beenmade insoluble in water (such as gelatin, casein, zein, starchderivatives, hydroxyethylcellulose, or polyvinyl alcohol) are present.The plastic supports, e.g., cellulose ester or polyester film, areprovided with a planographic surface, e.g., by saponification or byproviding the surface with a planographic layer, such as a layer of thecomposition described above in connection with the paper supports. Inorder that such layers may be fixed on a plastic film, the surface ofthe film may have undergone in a known way a treatment for making itmore susceptible to coatings of this kind, or it is provided with one ormore socalled adhesive layers. The aluminum supports have as surface tobe sensitized, for instance, an aluminum oxide skin (preferably abohmite skin), a silicate coating, or a planographic filler-bindercoating of the above-mentioned type.

Many of the diazo compounds according to the invention can be usedadvantageously for the sensitization of planographic plates for thediazo-type process. Compounds according to the invention which areparticularly suitable for the sensitization of such lithographicsurfaces are those in which R is a phenyl group which may be substitutedor nonsubstituted. They give plainly visible and sharp azo dyestuffimages which absorb ink readily and selectively when in the developingliquid an actively coupling aromatic hydroxyl compound formingoleophilic azo dyestuffs, such as phloroglucinol, resorcinol, or2,3-dihydroxynaphthalene, is incorporated.

The following examples further illustrate the practice and advantages ofthe invention.

EXAMPLE I In an autoclave 2,3,4-trichloro-l-nitrobenzene is converted byreaction with ammonia at C. into 3,4-dichloro-2- amino-l-nitrobenzene(melting point 162 C). This compound is boiled withN-methyl-N-cyclohexylamine to form 4-N-methyl-N-cyclohexylamino-S-chloro-Z-amino-l-nitrobenzene (melting point77-78 C.), which is diazotized with nitrosyl sulphuric acid in glacialacetic acid at a temperature of l520 C., after which cuprous chlorideand hydrochloric acid are added to the reaction mixture. Afterneutralization, the 4-N-methyl-N-cyclohexylamino-2,3-dichloro-l-nitrobenzene is extracted withether and obtained by evaporation of the ether.

After purification, the product thus obtained is dissolved in ethanol,along with ethylmercaptan and potassium hydroxide, and boiled. Thereaction mixture is poured out on ice and the 4-N-methyl-N-cyclohexylamino-3-chloro-2-ethylthiol nitrobenzene is obtainedby extraction with ether and evaporation of the ether from the extract.

The nitro compound is dissolved in glacial acetic acid and reduced withzinc powder. The reaction mixture is neutralized. The amino compound isextracted with ether, and after evaporation of the ether the residue isdissolved in a mixture of glacial acetic acid and hydrochloric acid. Atabout 5 C. an aqueous solution of sodium nitrite is added dropwise tothis solution to obtain the diazo compound which is brought to the formof the chlorozincate.

In an acid aqueous solution the4-N-methyl-N-cyclohexylamino-3-chloro-2-ethylthiobenzene diazoniumchlorozincate thus produced shows maximum absorption at 4120A., withE,,, ,=29,000. The compound is very suitable for the sensitization ofdiazo-type material.

EXAMPLE II 4-Tosylamino-2,3-dichloro-l-nitrobenzene (melting point 147C.), Obtained by tosylating 2,3-dichloro-aniline in the known way andnitrating the tosylamino compound in glacial acetic acid with thetheoretically required quantity of nitric acid, is dissolved in amixture of ethyleneglycolmonomethyl ether and water, and then methylatedwith dimethyl sulphate.

The 4-N-methyl-N-tosylamino-2,3-dichloro-l-nitrobenzene thus obtained(melting point l38-140 C.) is converted with a mixture of 90 parts beweight of sulphuric acid and 10 parts by weight of water at 50-60 C.into 4-methylamino-2,3- dichloro-l-nitrobenzene (melting point l62"-163C.). This product is methylated by boiling with a mixture offormaldehyde, formic acid, and acetic anhydride to form4-dimethylamino-2, 3-dichloro-1-nitrobenzene (melting point 80 C.). Thiscompound is dissolved along with ethylmercaptan and potassium hydroxidein ethanol and boiled. The 4-dimethylamino-3-chloro-2-ethylthio-1-nitrobenzene thus obtained (meltingpoint 37f38 C.) is catalytically reduced in ethyl acetate.

The resulting 4-dimethylamino-3-chloro-2-ethylthioaniline is diazotizedat -5 C. in dilute hydrochloric acid with sodium nitrite, and the diazocompound obtained is brought to the form of the chlorozincate.

EXAMPLE Ill The nitro-group in 3-chloro-2-fluoro-l-nitrobenzene isreduced with stannous chloride and hydrochloric acid to form the aminocompound which is tosylated in the known way. The tosylamino compound isnitrated with nitric acid to form 4-p-tosylamino-3-fluoro-2-chlorol-nitrobenzene (melting point 129-130 C.). This compound is methylatedwith dimethyl sulphate, and then the tosylamino group is saponified withsulphuric acid. The monomethylamino compound (melting point 143 C.) ismethylated with p-formaldehyde, formic acid, and acetic anhydride. The4-dimethyl-amino-3-fluoro-2- chloro-l-nitrobenzene thus obtained(melting point 102 C.) is converted with p-tolylmercaptan and potassiumhydroxide into 4-dimethylamino-3-fluoro-2-(4 -methylphenylthio)- lnitrobenzene (melting point 95 C.). This nitro compound is reduced withzinc dust and acetic acid, after which the amine thus obtained isdiazotized, and the diazo compound obtained is brought to the form ofthe chlorozincate.

EXAMPLE IV 2,3-dichloro-l-nitrobenzene is converted in an autoclave byreaction with ammonia, into 3-chloro-2-amino-lnitrobenzene (meltingpoint 75 C.). This product is diazotized and converted with cuprousbromide according to Sandmeyer into 3-chloro-2-bromo-l-nitrobenzene.Analogously to the method described in Example 111, from this compoundthe 4-dimethy1amino-3-bromo2-(4'-methylphenylthio)-l-nitrobenzene(melting point 212 C.) is produced, from which the diazo compound isobtained, by reduction and diazotization, in the form of thechlorozincate.

EXAMPLE V The diazo compound 4-dimethylamino-3-chloro-2-ethylthiobenzene diazonium chloride, zinc chloride double salt, producedaccording to Example 11, is converted in the following ways into thediazosulphonate, the diazosulphone and the diazoamine, respectively:

a. Diazosulphonate 103.5 g. of the said diazo compound is dissolved in150 ml. of 5 N hydrochloric acid and as much water as is required toobtain a clear solution. After cooling to 0 C., a solution of 37.8 g. ofsodium sulphite and 51.3 g. of sodium carbonate in 450 ml. of water isadded dropwise with stirring to the solution. When this solution hasbeen completely added, the mixture is stirred for another minutes. Thediazosulphonate is subsequently precipitated with the aid of sodiumchloride. The precipitate is sucked off and recrystallized from ethanol(96 percent). In an aqueous solution the diazosulphonate thus obtainedhas an absorption maximum with an E-value of 8750 at 3630A.

b. Diazosulphone 43 g. of the said diazo compound is dissolved in 35 ml.of hydrochloric acid (s.g. 1.19) and as much water as is required toobtain a clear solution. The solution is cooled to 0 C., and then asolution of 41 g. of the sodium salt of p-toluenesulphinic acid, and

25 g. ofsoda in 500 ml. of water is added. After the addition themixture is stirred for another 20 minutes and then the precipitate issucked off. The product thus obtained, dissolved in chloroform, has anabsorption maximum with an E-value of 16,600 at 4260A.

c. Diazoamine 170 g. of the said diazo compound is dissolved in 380 ml.of hydrochloric acid (1.2 N) and as much water as is required to obtaina clear solution. The solution is cooled at 10 C. Then a solution of 50g. of sarcosine and g. of sodium bicarbonate in 1250 ml. of water isadded dropwise with stirring. After this, the stirring is continued foranother 15 minutes. Then g. of sodium carbonate is added, and thediazoamine is precipitated with sodium chloride. After half an hoursstirring, the oily substance is decanted and dissolved in chloroform.The solution thus obtained is made anhydrous after which the diazoamineis precipitated with petroleum ether. The precipitate is washed withpetroleum ether and dried in a desiccator. An aqueous solution of thediazoamine buffered to pH 9 with borax has an absorption maximum with anE-value of 13,560 at 2720A, and with an E-value of 14,300 at 3 A.

EXAMPLE VI A mother liquor is produced, which contains 30 g. of tartaricacid 20 g. of the sodium salt of naphtalene 1,3,6-trisulphonic acid 40g. of 2.4-dihydroxybenzoic acid lB-hydroxy-ethylamide 20 g. ofsulphosalicylic acid 300 ml. ofethanol (96 percent) and 700 ml. ofwater.

Of this liquid, 3 portions of 300 ml. each are taken.

A. To the first portion is added 25 g. of4-dimethylamino-3-chloro-2-ethylthio-benzene diazonium chloride, zincchloride double salt.

B. To the second portion is added 27 g. of4-morpholino-2,S-diethoxybenzen diazonium chloride, zinc chloride doublesalt.

C. To the third portion is added 20 g. of4-dimethylamino-3-methoxybenzene diazonium chloride, zinc chloridedouble salt.

With each of the sensitizing liquids sized natural tracing paper of 80g./m. is sensitized. After drying, of each of the three diazo-typematerials a first sheet is imagewise exposed under a transparent inkdrawing until underneath the transparent portions of the drawing all thediazo compound has bleached out. The copies are developed in ammoniavapor. They show a brown image. Their background is transparent, but thebackground of the copy on sheet A is markedly clearer than that of thecopies on sheets B and C, and has greater transmission for the copyingradiation commonly used in the diazo-type process. Furthermore, theimage of the copy on sheet B has much lower density for this radiationthan the image on the other copies.

A second sheet of each of the three light-sensitive materials is storedfor 48 hours in a space in which a temperature of 50 C. prevails and thehumidity is 4%percent. The sheets are then developed in ammonia vapor.On sheet C after development practically no azo dyestuff is present,while on sheets A and B a large quantity of azo dyestuff is clearlypresent.

EXAMPLE Vll A cellulose acetate butyrate layer provided on apolyethylene terephthalate film is sensitized with a solution whichcontains 26 g. of 4-dimethylamino-3-chloro-2-isobutylthiobenzenediazonium chloride, zinc chloride double salt 50 g. of citric acid 30 g.of sulphosalicylic acid 30 g. of 3-(2'-hydroxyethoxy)phenol 50 ml. ofglacial acetic acid and 950 ml. of methylglycol, and dried.

A sheet of the light-sensitive polyester material thus obtained isimagewise exposed underneath a pencil drawing on tracing paper untilunderneath the transparent portions of the drawing the diazo compoundhas largely bleached out. The copy shows a brown image on a foggy palebrown background. The copy is eminently suited for further copying ondiazo-type material.

EXAMPLE Vlll White base paper of 80 g./m. for the diazo-type process issensitized with a solution containing 16.8 g. of4-dimethylamino-3-chloro-2-(2'-hydroxyethylthio)-benzene diazoniumchloride, stannic chloride double salt 40 g. of tartaric acid 10 g. ofthiourea 12.5 g. of 8-hydroxy l,2d]-naphthimidazole 10 ml. ofhydrochloric acid (s.g. 1.19) 30 ml. of isopropanol 20 g. of caffein and10 g. of N,N'-dimethylurea in 1000 ml. ofwater, and dried. A sheet ofthe light-sensitive diazo-type paper thus obtained is imagewise exposedand developed as described in Example VI. The copy shows a violet imageon a clear white background.

EXAMPLE lX White base paper of 80 g./m. for the diazo-type process issensitized with a liquid containing 30 g. of4-N-methyl-N-benzylamino-3-chloro-2-ethylthiobenzene diazonium chloride,stannic chloride double salt 5 g. of tartaric acid and 30 ml. of anaqueous polyvinyl acetate dispersion having a content of solid matter of50 percent and an average particle size of l-3 microns, in

100 ml. of water, and dried.

A sheet of the diazo-type paper thus obtained is imagewise exposedunderneath a pencil drawing on tracing paper until underneath thetransparent portions of the drawing substantially all the diazo compoundhas bleached out, and is then developed with the following developer:

6.5 g. of phloroglucinol 4 g. of resorcinol l g. of thiourea 2 g. of thesodium salt of dibutylnaphthalene sulphonic acid l4 g. of sodium formate22 g. of sodium benzoate 49 g. of trisodium citrate (2 aq.) and L2 g. ofcitric acid in 1000 ml. of water. The pH of this liquid is about 6.5.

The copy shows a dark image on a foggy background.

If in the above sensitizing liquid instead of the said diazo compound anequivalent quantity of the diazo compound produced according to examplelll is used, a copy with a black image on a foggy grey background isobtained. If in the above sensitizing liquid and the said diazo compoundis replaced by the compound produced according to example IV, copieswith a black image on a foggy grey background are also obtained.

EXAMPLE X A. A sheet of white base paper of 80 g./m. for the diazotypeprocess is sensitized with a liquid containing 24 g. of4-N-methyl-N-cyclohexylaminc-3-chloro-2- ethylthio-benzene diazoniumchloride, zinc chloride double salt 5 g. of tartaric acid and 30 ml. ofpolyvinyl acetate dispersion in 1000 ml. of water, and dried.

B. A sheet of white base paper of g./m.' for the diazotype process issensitized with a liquid containing 20 g. of4-N-methyl-N-cyclohexylamino-3-chlorobenzene diazonium chloride, zincchloride double salt 5 g. of tartaric acid and 30 ml. of polyvinylacetate dispersion in 1000 ml. of water, and dried.

Strips of sheets A and B are exposed underneath a transparent inkdrawing until underneath the transparent portions of the drawing all thediazo compound has bleached out. it then appears that strip A ismarkedly more light-sensitive than strip B. The strips are developedwith the following developer:

30 g. of thiourea 5.4 g. of phloroglucinol 6.5 g. of resorcinol 1 g. ofpotassium salt of hydrquinone monosulphonic acid 5 g. of sorbitol 15 g.of beet sugar 50 g. of potassium tetraborate (5 aq.) and L5 g. of thesodium salt of isopropylnaphthalene sulphonic acid in 1000 ml. of water.The pH of this liquid is about 9.

The strip A shows a darker azo dyestufi image than strip B. Thewater-Fastness of the azo dyestuff is markedly greater in sheet A thanin sheet B. if the strips of the sheets A and B are developed, afterimagewise exposure, with the developer described in Example IX, a stripA shows a violet-black, Strip B a dark brown azo dyestuff image. The azodyestuff image on strip A is sharper because the azo dyestuff bleedsless upon development than in the case of strip 8.

EXAMPLE Xl A paper planographic plate of the Rotaprint" C3-type issensitized with a solution of 24 g. of4-dimethylamino-3-chloro-2-(4'-methylphenylthiobenzene diazoniumchloride, zinc chloride double salt in 200 ml. of ethanol (96 percent)and 800 ml. of water, and dried.

The light-sensitive planographic plate thus obtained is imagewiseexposed underneath a positive original until underneath the transparentportions thereof all the diazo compound has bleached out, and is thendeveloped with a solution containing 12 g. of phloroglucinol 87 g. ofdisodium hydrogen phosphate (2 aq.) and l l g. of citric acid in 1000ml. of water, and sponged off with water; it shows a brown image on awhite background. The image absorbs printing ink in a satisfactorilyselective way. On an offset printer l50 good prints are made of theplate.

In the above sensitizing liquid the diazo compound used can be replacedby the diazonium salt obtained from any of the following amines:

a. 4-dimethylamino-3-chloro-2-(4'-methoxyphenylthio)aniline b.4-dimethylamino-3-chloro-2-(2-methylphenylthio)aniline c.4-dimethylamino-3-bromo-2-(4'-methylphenylthio)aniline d.4-N-methyl-N-benzylamino-3-chloro-2-(4'-methylphenylthio)aniline 3.4-N-methyl-N-cyclohexylamino-3-chloro-2- ethylthioaniline. The plateobtained with compound e gives approximately 50 good prints. With theother plates at least 100-200 good prints can be made.

EXAMPLE Xll EXAMPLE Xlll Tracing paper is coated with a solutioncontaining 20 g. of the diazosulphone produced according to example g.of resorcinol 10 g. of polyvinyl acetate and 20 g. of oxalic acid in1000 ml. of acetone, and dried.

By imagewise exposure and development as described in example Xll a copyhaving a yellow-brown azo dyestuff image on a transparent background isobtained.

EXAMPLE XIV ln 1 liter of water there is dissolved about 30 g. of thediazoamine produced according to example V. 10 ml. of hydrochloric acid(s.g. 1.19), g. of citric acid, and 30 ml. of polyvinyl acetatedispersion are added. With the sensitizing liquid thus produced, whitebase paper of 80 g./m. for the diazo-type process is sensitized. Afterthe sensitization the paper is dried.

A copy is made with the paper in the way described in example 1x.

I. A light-sensitive diazo compound of the formula NQX in which N,X isadiazo group and X is an anion of an acidic compound; R, is an alkylgroup having up to six carbon atoms, a phenyl or naphthyl group, or aphenylalkyl group having up to two carbon atoms in the alkyl partthereof;

Y is a chlorine, fluorine or bromine atom;

R, is an alkyl group having up to six carbon atoms, a phenylalkyl grouphaving up to two carbon atoms in the alkyl part thereof, or a benzylgroup or a cycloalkyl group having five or six carbon atoms; and R is analkyl group having up to six carbon atoms; or R and R together with thenitrogen atom to which they attach form a saturated 5- or 6-memberedheterocyclic ring.

2. A diazo compound according to claim 1, wherein R, is an alkyl grouphaving at most five carbon atoms.

3. A diazo compound according to claim 1, wherein R, is a phenyl group.

4. A diazo compound according to claim 1, wherein R is an alkyl grouphaving at most four carbon atoms and R, is an alkyl group having at mostfour carbon atoms or a benzyl or cyclohexyl group.

5. A diazo compound according to claim 1, that is, a 4-dimethylamino-3-(chloro, fluoro or bromo)-2- methylthiobenzene diazoniumsalt.

6. A diazo compound according to claim 1, that is, a 4- (methyl)(cyclohexyl)amino-3-(chloro, fluoro or bromo)-2- methylthiobenzenediazonium salt.

7. A diazo compound according to claim 1, that is, a 4-dimethylamino-3-(chloro, fluoro or bromo)-2-(4'- methylphenylthio)benzene diazonium salt.

8. A light-sensitive diazo compound of the formula Nzx in which M N,X isa diazo group and X is an anion of an acidic compound;

R, is an alkyl group having up to six carbon atoms or a phenyl, naphthylor phenethyl group; R is an alkyl group having up to six carbon atoms ora phenethyl, benzyl or cyclohexyl group; and R, is an alkyl group havingup to six carbon atoms; or R and R, together with the nitrogen atom towhich they attach form a saturated 5- or 6-membered heterocyclic ring. 79. Light-sensitive material comprising a support carrying thereon alight-sensitive layer containing a light-sensitive diazo compoundaccording to claim 8. 3 l0. Light-sensitive material, comprising asupport carrying thereon a light-sensitive layer containing alight-sensitive diazo compound of the formula in which N X is a diazogroup and X is an anion of an acidic compound;

R, is an alkyl group having up to six carbon atoms, a phenyl or naphthylgroup, or a phenylalkyl group having up to two carbon atoms in the alkylpart thereof;

Y is a chlorine, fluorine or bromine atom;

R, is an alkyl group having up to six carbon atoms, a phenylalkyl grouphaving up to two carbon atoms in the alkyl part thereof, or a benzylgroup or a cycloalkyl group having five or six carbon atoms and R, is analkyl group having up to six carbon atoms;

or R and R together with the nitrogen atom to which they attach form asaturated 5- or o-mcmbered heterocyclic ring.

11. Light-sensitive material according to claim 10, wherein R, is analkyl group having at most five carbon atoms.

12. Light-sensitive material according to claim 10, suitable for use asa diazo-type planographic plate and wherein R, is a phenyl group.

13. Light-sensitive material according to claim 10, wherein R is analkyl group having at most four carbon atoms and R, is an alkyl grouphaving at most four carbon atoms or a benzyl or cyclohexyl group.

14. Light-sensitive material according to claim 10, wherein saidcompound is a 4-dimethylamino-3-(chloro, fluoro orbromo)-2-methylthiobenzene diazonium salt.

15. Light-sensitive material according to claim 10, wherein saidcompound is a 4-dimethylamino-3-(chloro, fluoro orbromo)-2-(4'-methylthio) benzene diazonium salt.

16. Light-sensitive material according to claim 10, wherein saidcompound is a 4-methylamino-3-(chloro, fluoro orbromo)-2(4'methyphenylthio) benzene diazonium salt.

t t IIK t UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 3,615,578 Dated October 26, 1971 Adrianus Marie Petrus Heotors andHubertus Johannes Nilhelmus Pecasse Assignors to Van Der Grinten N.V.,

of Venlo, Netherlands.

It is certified that error appears in the aboveidentified patent andthat said Letters Patent are hereby corrected as shown below:

Col. 2, line 63, insert and read "l-ear1:ox yethylmercaptan;

before "phenethylmercaptan" line 2, "3 N should read "-N".

Col. 3,

Claim 15, line 2, dimethylamino" should read (methyl)(cyclohexyl) aminoand line 3, U-methylthio) should read methylthio Claim 16, line 2,"methylamino" should read dimethylamino Signed and sealed this 15th dayof May 1973.

(SEAL) Attest:

ROBERT GOTTSCHALK EDWARD M. FLETCHER,JR.

Commissioner of Patents Attesting Officer

2. A diazo compound according to claim 1, wherein R1 is an alkyl grouphaving at most five carbon atoms.
 3. A diazo compound according to claim1, wherein R1 is a phenyl group.
 4. A diazo compound according to claim1, wherein R3 is an alkyl group having at most four carbon atoms and R2is an alkyl group having at most four carbon atoms or a benzyl orcyclohexyl group.
 5. A diazo compound according to claim 1, that is, a4-dimethylamino-3-(chloro, fluoro or bromo)-2-methylthiobenzenediazonium salt.
 6. A diazo compound according to claim 1, that is, a4-(methyl) (cyclohexyl)amino-3-(chloro, fluoro orbromo)-2-methylthiobenzene diazonium salt.
 7. A diazo compound accordingto claim 1, that is, a 4-dimethylamino-3-(chloro, fluoro orbromo)-2-(4-methylphenylthio) benzene diazonium salt.
 8. Alight-sensitive diazo compound of the formula
 9. Light-sensitivematerial comprising a support carrying thereon a light-sensitive layercontaining a light-sensitive diazo compound according to claim
 8. 10.Light-sensitive material, comprising a support carrying thereon alight-sensitive layer containing a light-sensitive diazo compound of theformula
 11. Light-sensitive material according to claim 10, wherein R1is an alkyl group having at most five carbon atoms.
 12. Light-sensitivematerial according to claim 10, suitable for use as a diazo-typeplanographic plate and wherein R1 is a phenyl group.
 13. Light-sensitivematerial according to claim 10, wherein R3 is an alkyl group having atmost four carbon atoms and R2 is an alkyl group having at most fourcarbon atoms or a benzyl or cyclohexyl group.
 14. Light-sensitivematerial according to claim 10, wherein said compound is a4-dimethylamino-3-(chloro, fluoro or bromo)-2-methylthiobenzenediazonium salt.
 15. Light-sensitive material according to claim 10,wherein said compound is a 4(methyl) (cyclohexyl) amino- 3-(chloro,fluoro or bromo)-2-methylthiobenzene diazonium salt.
 16. Light-sensitivematerial according to claim 10, wherein said compound is a4-methylamino-3-(chloro, fluoro or bromo)-2(4''methyphenylthio) benzenediazonium salt.